Pressing tools, attachments for pressing tools and methods of the above mentioned type are known, for example from the drinking water sector and heating installation sector. The tools and methods can be used to radially pressing together workpieces such as fittings, pipes, bushings or the like. To press together radially means here substantially to deform, by means of a tong-like closing movement of two pivot elements having pressing jaws, two workpieces which overlap one another at least partially and thus to connect them in a permanent manner.
However, this approach can be disadvantageous. With pressing tools and methods provided for this purpose, for example, it is made very difficult to apply an all-around homogeneous pressing force onto the workpieces to be pressed together. Pipes and fittings can have a rotation symmetric and essentially round shape prior to the pressing process. Due to inhomogeneously acting pressing forces, this symmetry can be disturbed at the joint between pipe and fitting after the pressing process, which on the one hand can affect the optical appearance and on the other hand the functionality of the connection.
Furthermore, the materials, in particular plastic or metals, of the workpieces loaded during the pressing process can have an inertia which is directed against the pressing forces. In the form of reset forces, this inertia can result in that the material deformed during the pressing process has the tendency to restore at least partially the initial state or the initial microstructure of the workpieces, respectively. This requires that the user of an inwardly acting pressing method or pressing tool, respectively, has to increase the pressing forces to be applied radially inwardly to obtain the desired pressing result. However, this represents a load on the materials of the workpieces to be pressed together which is beyond the usual level and thus is principally undesired.